Relationship of Fruit and Vegetable Intake with Serum C-Reactive Protein Levels in College-Aged Students
All chronic diseases are caused by inflammation. Diets high in fruits and vegetables are associated with lower levels of inflammation, and lower risks of chronic diseases including cardiovascular disease and diabetes. C-reactive protein (CRP), an inflammatory marker, provides insight on the level of inflammation therefore potential risks of chronic diseases. A low CRP level is classified as less than 1 mg/L; a medium CRP level is between 1mg/L and 3mg/L, and a high CRP is > 3mg/L.
The purpose of this study was to determine whether high fruit and vegetable intake is inversely associated with serum CRP levels in college-aged subjects.
Methods: the Institutional Review Board (IRB) of the College of St. Benedict/St. John's University approved the study and informed consent was obtained from all participants. Students from a college nutrition class were asked to complete a seven-day diet record and a pre-study survey, screening for factors that affect CRP levels, such as smoking, alcohol consumption, recent injury, activity level and stress level. Twenty-seven subjects (six males, 21 females) participated. CRP was measured with a 50-microliter sample of blood using hs-CRP cassette and the Cholestech LDX System. Participants' seven-day diet records sorted into respective groups based on the number of fruits and vegetables consumed per day and the variety. The high fruit and vegetable [HFV] group (n=11) consumed more than five servings with five different types of fruit and vegetables per day; the medium fruit and vegetable (MFV) group (n=7) consumed between two and five servings a day, with some variety present; and the low fruit and vegetable [LFV] group (n=10) consumed less than two servings a day, with little variety within the seven-day diet period.
Results: Serum CRP levels were inversely associated with fruit and vegetable intake. The CRP mean ± SD for the HFV group was 0.60 ± 0.60 mg/L; for the MFV group, 0.95 ± 1.2 mg/L; and for the LFV group, 3.43 ± 3.25 mg/L. Analysis of variance was used to determine the difference between groups; the CRP mean of the HFV group is statistically different from the CRP mean for the LFV group [p = 0.013.] There were no high CRP values in the HFV group; in fact 82% [9/11] in HFV group had low CRP values while 50% of the individuals [5/10] in the LFV had high CRP values.
Conclusions: Individuals in the HFV or MFV groups on average have CRP levels below 1 mg/L [low CRP] but those in the LFV group have on average CRP values in the high range [CRP > 3mg/L]. Five individuals had elevated CRP levels even in this young college aged population indicating inflammation and if these elevated levels are chronic, an increased risk for developing disease. The UDSA Dietary Guidelines' recommendation of five or more servings of a variety of fruits and vegetables per day appears to be good advice to keep serum C-reactive levels low.
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Research Advisor: Amy Olson, PhD, RDN, LD